Database Management System (DBMS) v DBMS
contains information about a particular enterprise § Collection of interrelated data § Set of programs to access the data § An environment that is both convenient and efficient to use
v Database
§ § § §
Applications:
Banking: all transactions Airlines: reservations, schedules Universities: registration, grades Sales: customers, products, purchases
Database Management Systems, R. Ramakrishnan and J. Gehrke
INFSCI2710
Instructor: Vladimir Zadorozhny
1
Why Use a DBMS? v Data
independence and efficient access. v Reduced application development time. v Data integrity and security. v Uniform data administration. v Concurrent access, recovery from crashes. v User-friendly declarative query language.
Database Management Systems, R. Ramakrishnan and J. Gehrke
INFSCI2710
Instructor: Vladimir Zadorozhny
2
Data Models v A
data model is a collection of concepts for describing data. v The relational model of data is the most widely used model today. § §
Main concept: relation, basically a table with rows and columns. Every relation has a schema, which describes the columns, or fields.
Database Management Systems, R. Ramakrishnan and J. Gehrke
INFSCI2710
Instructor: Vladimir Zadorozhny
3
SQL
v
SQL: widely used non-procedural database query language § Find the name of the customer with customer-id 192-83-7465 select customer.customer_name from customer where customer.customer_id = ‘192-83-7465’
Database Management Systems, R. Ramakrishnan and J. Gehrke
INFSCI2710
Instructor: Vladimir Zadorozhny
4
Database Design The process of designing the general structure of the database: v Logical Design – requires that we find a “good” collection of relation schemas. § Business decision – What attributes should we record in the database? § IS decision – What relation schemas should we have and how should the attributes be distributed among the various relation schemas? v Physical
Design – Deciding on the physical layout of the database
Database Management Systems, R. Ramakrishnan and J. Gehrke
INFSCI2710
Instructor: Vladimir Zadorozhny
5
Database Architecture The architecture of a database systems is greatly influenced by the underlying computer system on which the database is running: v Centralized (our focus in this class) v Client-server v Parallel (multi-processor) v Distributed
Database Management Systems, R. Ramakrishnan and J. Gehrke
INFSCI2710
Instructor: Vladimir Zadorozhny
6
Summary v DBMS
used to maintain, query large datasets. v Benefits include recovery from system crashes, concurrent access, quick application development, data integrity and security. v Levels of abstraction give data independence. v A DBMS typically has a layered architecture. v DB professionals hold responsible jobs. v DBMS is one of the broadest, most exciting areas in R&D. Database Management Systems, R. Ramakrishnan and J. Gehrke
INFSCI2710
Instructor: Vladimir Zadorozhny
7